This application relates to microwave (MW) and radio frequency (RF) components and devices and their applications.
Impedance matching is a condition under which the input impedance matches the output impedance in a microwave or RF device to reduce loss in transmitting a microwave signal. Various microwave and RF devices use LC circuits based on lumped components, microwave stubs, or impedance transformers to achieve the desired impedance matching. These techniques, however, have their limitations. For example, the LC circuits for impedance matching are often limited to low microwave frequencies. The microwave stubs and impedance transformers typically provide impedance matching within about one half of an octave and the corresponding bandwidth may not be sufficiently narrow for some single-frequency microwave and RF devices.